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Odontaspis
''Odontaspis'' (from el, ὀδούς 'tooth') and el, ἀσπίς 'shield') is a genus of sand shark with two extant species. Description Bigeye sand tigers can reach a length of about and smalltooth sand tigers of about 4.1 m. They are large-bodied sharks with long, conical snouts, broad-based dorsal and anal fins, and an asymmetrical caudal fin with a strong lower lobe. Their teeth are large, with prominent narrow cusps. They are distinguished from the similar genus '' Carcharias'' by the absence of crushing posterior teeth.Bourdon, J''Odontaspis'' Agassiz 1838 ''Elasmo.com''. Retrieved on December 24, 2008. These bottom dwelling, deepwater sharks can be found in temperate and tropical waters of all the oceans. Extant species * '' Odontaspis ferox'' ( A. Risso, 1810) (smalltooth sand tiger) * '' Odontaspis noronhai'' ( Maul, 1955) (bigeye sand tiger) Extinct species Extinct species within this genus include: * ''Odontaspis aculeatus'' Capetta & Case, 1975 * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bigeye Sand Tiger
The bigeye sand tiger (''Odontaspis noronhai'') is an extremely rare species of mackerel shark in the family Odontaspididae, with a possible worldwide distribution. A large, bulky species reaching at least in length, the bigeye sand tiger has a long bulbous snout, large orange eyes without nictitating membranes, and a capacious mouth with the narrow teeth prominently exposed. It can be distinguished from the similar smalltooth sand tiger (''O. ferox'') by its teeth, which have only one lateral cusplet on each side, and by its uniformly dark brown color. Inhabiting continental margins and oceanic waters at depths of , the bigeye sand tiger may make vertical and horizontal migratory movements. It feeds on bony fishes and squid, and its sizable eyes and dark coloration suggest that it may spend most of its time in the mesopelagic zone. Reproduction is probably viviparous with oophagous embryos like in other mackerel shark species. This shark is caught incidentally by commercial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smalltooth Sand Tiger
The smalltooth sand tiger or bumpytail ragged-tooth (''Odontaspis ferox'') is a species of mackerel shark in the family Odontaspididae, with a patchy but worldwide distribution in tropical and warm temperate waters. They usually inhabit deepwater rocky habitats, though they are occasionally encountered in shallow water, and have been known to return to the same location year after year. This rare species is often mistaken for the much more common grey nurse shark (''Carcharias taurus''), from which it can be distinguished by its first dorsal fin, which is larger than the second and placed further forward. It grows to at least 4.1 m (13.5 ft) in length. Very little is known of the biology and behavior of the smalltooth sand tiger. It is an active predator of benthic bony fishes, invertebrates, and cartilaginous fishes. This species is thought to be ovoviviparous with oophagous embryos like other mackerel sharks. In contrast to its formidable size and appearance, this s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odontaspis
''Odontaspis'' (from el, ὀδούς 'tooth') and el, ἀσπίς 'shield') is a genus of sand shark with two extant species. Description Bigeye sand tigers can reach a length of about and smalltooth sand tigers of about 4.1 m. They are large-bodied sharks with long, conical snouts, broad-based dorsal and anal fins, and an asymmetrical caudal fin with a strong lower lobe. Their teeth are large, with prominent narrow cusps. They are distinguished from the similar genus '' Carcharias'' by the absence of crushing posterior teeth.Bourdon, J''Odontaspis'' Agassiz 1838 ''Elasmo.com''. Retrieved on December 24, 2008. These bottom dwelling, deepwater sharks can be found in temperate and tropical waters of all the oceans. Extant species * '' Odontaspis ferox'' ( A. Risso, 1810) (smalltooth sand tiger) * '' Odontaspis noronhai'' ( Maul, 1955) (bigeye sand tiger) Extinct species Extinct species within this genus include: * ''Odontaspis aculeatus'' Capetta & Case, 1975 * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Prehistoric Cartilaginous Fish
This list of prehistoric cartilaginous fish genera is an attempt to create a comprehensive listing of all genera that have ever been included in the class chondrichthyes ''and'' are known from the fossil record. This list excludes purely vernacular terms, genera that are now considered invalid, doubtful (nomina dubia), or were not formally published (nomina nuda), as well as junior synonyms of more established names, and genera that are no longer considered to be cartilaginous fish. It includes all commonly accepted genera. This list currently contains 804 generic names. * Extinct genera are marked by a dagger (†). * Extant taxon genera are bolded. Naming conventions and terminology Naming conventions and terminology follow the International Code of Zoological Nomenclature. Technical terms used include: * Junior synonym: A name which describes the same taxon as a previously published name. If two or more genera are formally designated and the type specimens are later assign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand Shark
Sand sharks, also known as sand tiger sharks, gray nurse sharks or ragged tooth sharks, are mackerel sharks of the family Odontaspididae. They are found worldwide in temperate and tropical waters. The three species are in two genera. Description The body tends to be brown with dark markings in the upper half. These markings disappear as they mature. Their needle-like teeth are highly adapted for impaling fish, their main prey. Their teeth are long, narrow, and very sharp with smooth edges, with one and on occasion two smaller cusplets on either side. Sand sharks have a large second dorsal fin. The sand shark can grow up to long, and most adults can weigh around . The average lifespan of both sexes is only about 7 years, though they may live longer in captivity. Location and origins The name sand shark comes from their tendency to migrate towards shoreline habitats, and they are often seen swimming around the ocean floor in the surf zone; at times, they come very close to shor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcharias
''Carcharias'' is a genus of sand tiger sharks belonging to the family Odontaspididae. Once bearing many prehistoric species, all have gone extinct with the exception of the critically endangered sand tiger shark. Description ''Carcharias'' are 2.5 m long on average. The maximum weight of the shark is 158.8 kg. Differentiating species of sharks is usually done by locating and measuring their fins. The second dorsal fin and the anal fin of ''Carcharias'' are very large. In fact, they are about equal in size. The pectoral fins are triangular and only slightly larger than the dorsal fins. The teeth are very long and narrow with sharp points. The teeth are smooth with no ridges. The tail is one third of the entire body size. Diet ''Carcharias'' species hunt bony fish, small sharks, rays, squids, crabs, and lobsters. Habitat Sand tiger sharks live in water depths ranging from 0 to 190 meters. They are found in the Pacific, Atlantic, and Indian oceans. They are commonl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shark Genera
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays. However, the term "shark" has also been used to refer to all extinct members of Chondrichthyes with a shark-like morphology, such as hybodonts and xenacanths. The oldest modern sharks are known from the Early Jurassic. They range in size from the small dwarf lanternshark (''Etmopterus perryi''), a deep sea species that is only in length, to the whale shark (''Rhincodon typus''), the largest fish in the world, which reaches approximately in length. Sharks are found in all seas and are common to depths up to . They generally do not live in freshwater, although there are a few known exceptions, such as the bull shark and the river shark, which can be found in both seawater and f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extant Cretaceous First Appearances
Extant is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Extant taxon, a taxon which is not extinct, such as an extant species * Extant Theatre Company, a disability arts organisation * ''Extant'' (TV series), an American television series * Hank Hall Hank Hall is a fictional character that appears in DC Comics. He first appeared in ''Showcase (comics), Showcase'' #75 (June 1968) as Hawk of Hawk and Dove. He later became the supervillain Monarch (comics), Monarch in the Shared universe#Corporat ..., also known as Extant, a DC Comics supervillain See also * Extent (other) {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary
The Quaternary ( ) is the current and most recent of the three period (geology), periods of the Cenozoic era (geology), Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today, although a third epoch, the Anthropocene, has been proposed but is not yet officially recognised by the ICS). The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino (geologist), Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four successive formations or "orders" ( it, quattro ord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
